We tend to go with the latter, and we cite the above video as proof. The U.K.'s Telegraph reports that a passenger named Bertan Atay recorded a short clip of the passengers aboard his Turkish Airline flight after an engine caught fire. The Telegraph says the "video captures the panic and confusion" of the moment, but we'd have to disagree. Everyone appears oddly calm, like the site of an engine fire wasn't cause for concern.
The passengers do allow themselves to murmur a bit once the lights go out, but that's about as panicked as they seem to get. And, fortunately, everything turned out OK. The pilot declared an emergency and brought the plane down to safety. No one was hurt.